Buffett, the world's third-richest person, told executives from newspapers he has acquired in recent months on Friday: "It's a great day for me. Today I had my 44th and last day of radiation."

Buffett, 82, disclosed in April he was diagnosed with Stage 1 prostate cancer. At the time, he said his case "is not remotely life-threatening or even debilitating in any meaningful way."

Buffett, widely considered the most successful investor of the last century, started daily radiation treatments at the Nebraska Medical Center in mid-July. He said the treatment would hinder his travels for about two months.

Buffett joked with executives about planning to live to be the oldest man alive, the Buffett-owned World-Herald said.

Berkshire Hathaway is a conglomerate that employs more than 270,000 people in more than 70 businesses around the world.

Buffett told investors in late February that Berkshire had identified his successor. He declined to say who it was and admitted that even the chosen one did not know.